1. Field of the Invention
The present invention relates to a wire fastening device for extending a wire between support bodies and a wire extending structure for constituting a handrail, a fence, etc. using the wire fastening devices.
2. Description of the Related Art
A wire extending structure is used for constituting a fence for exhibiting entrance through a railing bar and indicating a boundary of a no-entry zone, and a wire guard for preventing people and vehicles form falling. The wire extending structure is installed on a flat or inclined floor or ground, and also vertically between a ceiling and a floor. Further, wires for the wire guard along a road and wires for architecture bear a load exerted on the structure. In any of the cases, one end of the wire is fixed to one support body and the other end of the wire is fixed to another support body. The wire extending structure has been widely adopted because of fine appearance of line design and good perspective view of background.
There have been proposed wire fixing devices for fixing ends of the wire on the support bodies in Japanese Utility-Model Publication No. 57-107472 and Japanese Patent Publication No. 8-93167. The wire fixing device disclosed in these publications comprises a fixing member for fixing on a support body, a connection member for connecting one end of the wire and a cap or casing. The fixing member has a proximal portion fixed to the support body by a screw or welding and a male thread formed at the other end. The connection member fixed to the end of the wire is attached to the fixing member by screwing on the male thread. The one end of the wire is fixed to the connection member by pinching it by a chuck or a stopper or by caulking. The cap is provided for covering the coming out portion of the wire from the connection member for improving appearance and often formed integrally with the connection member.
In these fixing devices, since the wire is fixed to the support body by rotating the connection member with respect to the fixing member, if the connection member is rotated by mischief after installation the wire easily looses tension. Further, since a pulling stroke of the wire by the threaded engagement between the fixing member and the connection member is small, a sufficient tension is not provided on the to wire when a length of the wire is too long for the pulling stroke, and contrary, where the wire is too short to fully screw the connection member into the fixing member so that an opening is formed between the connection member and the fixing member.
Furthermore, the connection of the end of the wire with the connection member by a chuck makes the connection member thick and deteriorates the appearance of the wire structure.
The connection members with one end of the wire caulked have to be rotated simultaneously making it hardly possible to install by one person.
An object of the present invention is to provide a wire fastening device and a wire extending structure to extend a wire between support bodies with an appropriate tension to enhance the appearance without deteriorating strength and to prevent mischief after installation.
The case has a cylindrical shape with one end closed and has a through hole at the one end for inserting one end of a wire and an engaging portion for engaging a stopper fixed to the one end of the wire. The case has a female thread on an inner circumference thereof.
The case has a cylindrical shape with one end closed and has a through hole at the one end for inserting one end of a wire and engaging portion for engaging a stopper fixed to the one end of the wire. The case has a female thread on an inner circumference thereof.
The pulling cylinder has a male thread on an outer circumference thereof to be engaged with the female thread of the case. The pulling cylinder has an inner diameter such that the pulling cylinder is fitted on a shank of the cap bolt and to abut a head of the cap bolt. The threads formed on the cap and the pulling cylinder may be of left-handed threads so as not to loosen the right-handed screwed fixing of the cap bolt when the pulling cylinder is rotated with respect to the case to pull the case with the wire.
A wire fastening device is set up by engaging the stopper fixed to one end of the wire with the case, and the cap bolt with the pulling cylinder fitted thereon is fixed to the terminal pole. The cap bolt is fixed to the terminal pole in various manners, such as welding, threaded engagement with a cap nut, or threaded engagement with an end bolt using a threaded spacer cylinder therebetween. The case with one end of the wire is fitted into the cap bolt to be engaged with the pulling cylinder by rotating the pulling cylinder.
Another wire fastening device is set up by inserting the other end of the wire into a through hole of the cap and fixing another stopper on the other end of the wire. The stopper may be fixed on the other end of the wire by caulking or set screws screwed in holes formed on the stopper.
The cap with the other end of the wire engaged therewith is fitted in the cap bolt fixed to another pole to be engaged with the pulling cylinder by rotating the pulling cylinder.
In the above manner, the wire is extended between one pole and another pole. Then, the pulling cylinder is rotated with respect to the case to pull the case towards the support body by the threaded engagement between the pulling cylinder and the case since the pulling cylinder is rotatably supported by the head of the cap bolt retaining an axial position thereof Thus the wire is strained with an appropriate tension by the axial movement of the case.
By setting the length of the pulling cylinder slightly shorter than the pulling distance of the wire, the pulling cylinder is fully inserted into and covered by the case when the wire is strained with an appropriate tension. If the case is rotated, the pulling cylinder rotates with the case but does not cause relative rotation between the case and the pulling cylinder, thereby preventing wire slack.
The pulling cylinder is rotated relatively to the case to be fully inserted into the case by a dedicated tool engaged with notches formed on the pulling cylinder, and thus the dedicated tool is necessary to loosen the threaded engagement between the case and the pulling cylinder to prevent mischiefs of the device. It is preferable to close an opening between the case and the pulling cylinder by sealing material after straining the wire. The case and the pulling cylinder may be fixed with each other not to permit the relative rotation therebetween after fastening the wire.
A spacer may be used for securing a space for a rotating operation of the pulling cylinder by the dedicated tool. The spacer cylinder has a female thread on an inner circumference thereof to be engaged with the male thread formed on the shank of the cap bolt.
Notches for engagement with a tool are provided in the pulling cylinder for easy rotation thereof. The notches may be a hexagonal nut formed integrally on the outer circumference and preferably are cutaways formed at a rear end closer to the support body to extend in the axial direction. With such cutaways, the pulling cylinder can be rotated by a dedicated tool engaged with the cutaways inserted from an opening of the case to be completely covered by the case so that the appearance of the fastening device is enhanced. The pulling cylinder can be further rotated by the dedicated tool after the pulling cylinder is completely covered by the case.
By rotating the pulling cylinder, the case is moved towards the support body. A spacer may be used for securing a space for operating the tool between the rear end of the case and the support body. By setting an outer diameter of the space ring smaller than an inner diameter of the case, the rear end of the case may cover the pulling cylinder and also the spacer to enhance the appearance of the connection between the fastening device and the support body. A space is formed between the fastening device and the support body when the wire extending structure is installed and this space may be preferable in design as a handrail or a fence.
A periphery of a front end of the pulling cylinder is abutted with the head of the cap bolt and a periphery of one end of the spacer is abutted with a rear end of the pulling cylinder to place the pulling cylinder in a stationary axial position on the shank of the cap bolt. A washer may be intervened between the pulling cylinder and the head of the cap bolt for smooth rotation of the pulling cylinder.
The connection between the pulling cylinder and the case is accomplished by threaded engagement of the male thread on the entire outer circumference of the pulling cylinder and the female thread on the inner circumference of the case to have strength in the pulling direction. The connection between the case and the wire is accomplished by engagement between the stopper fixed to one end of the wire and an engaging portion of the case to have sufficient strength and reduce diameters of the cap bolt and the case.
The wire extending structure is constituted by a wire with both ends fixed to stoppers and the wire fastening devices engaged with the both ends of the wire.
The cap bolt of one wire fastening device is fixed to one support body and the cap engaged with one end of the wire is fitted to the cap bolt and screwed on the pulling cylinder to connect the one end of the wire with the one support body. Likewise, the cap bolt of another wire fastening device is fixed to another support body and the cap engaged with the other end of the wire is fitted to the cap bolt and screwed on the pulling cylinder to connect the other end of the wire with the another support body.
A plurality of units of the above wire extending structure between one support body and the other support body can be provided in series to extend the shielding effect or the wire extending structure can be extended by using the other support body of one wire extending structure as one support body of the adjacent wire extending structure.
When the wire extending structure is provided in series, the adjacent wire fastening devices with a connecting pole between may be connected by one grub screw arranged to penetrate the connecting pole in the direction of the wires. With this arrangement, the adjacent wire fastening devices are aligned in a line and an attaching work of the adjacent wire fastening devices is reduced.
The spacer may have a boss formed integrally therewith and can be used for constituting the wire extending structure on an inclined floor. The boss is rotatably supported by a shaft inserted into the supporting pole in a direction perpendicular to the wire axis. With this arrangement, the spacer can swing about the shaft in accordance with an angle formed between the wire and the support pole to align the wire axes on both sides of the connecting pole.
The support body includes a ceiling, a floor, a wall, a polygonal or annular frame as well as a pole. The wire may be not only a so-called wire by twisting metal lines such as stainless steel lines but also a thread, a string, a cord, a rope, a line made of fibers, resin, metal, etc.
An intermediate support body may be used for merely supporting the wire by a through hole between the one support body and the other support body. The through hole for inserting the wire preferably has substantially the same diameter as that of the wire for a handrail or a fence so as to prevent noises caused by a strong wind and enhance the design.
In order to retain the tension of the wire and absorb a difference between a length the wire and a distance between the one support body and the other support body, a resilient member such as a coil spring may be used to intervene between the case and the stopper fixed to one end of the wire.
A scale of the wire extending structure, and thus diameter of the wire and dimension of the support body are not restricted. In general, the support body and the wire fastening device has a greater dimension when the wire has a greater diameter.
The wire fastening device of the present invention may be utilized for suspending an article vertically.